Large centrifugation systems typically use a rotor for holding sample containers which contain the sample to be separated. The rotor is covered by a rotor lid and then placed into an instrument chamber wherein the rotor is spun during centrifugation. Typically, the instrument chamber is evacuated for the centrifugation run to reduce the effects of windage and heat generation.
If the rotor lid is properly sealed, then the air within the interior chamber of the sealed rotor remains at atmospheric pressure and does not leak into the evacuated instrument chamber. Upon completion of the centrifugation run, the instrument chamber is vented back to atmospheric pressure and the rotor lid is easily removed from the rotor.
However, if the rotor lid seals are not properly maintained or if the seals have been compromised, then air from the interior chamber of the rotor will escape and leak into the evacuated instrument chamber during a centrifugation run. This creates a low pressure system within the rotor. When the instrument chamber is returned to atmospheric pressure, this pressure will push the lid tightly onto the rotor body thus creating a vacuum locked lid.
A good seal of the rotor lid is also desirable in order to prevent leakage of the material undergoing centrifugation. This is especially important where toxic and other bio-hazardous materials are concerned. If breakage occurs within the rotor chamber, the analyte may spill and/or release hazardous vapors, resulting in a positive pressure within the rotor chamber. Such vapors may release in a violent manner when the rotor lid is removed, exposing laboratory personnel to harmful material.
It is therefore desirous to have a rotor lid system which can provide venting in situations where a negative pressure is created within the rotor chamber. It is also desirable that the rotor lid system provide a safe venting direction in cases where a positive pressure develops within the rotor chamber so that venting of hazardous materials can occur without risk to the user.